ADA and infectious meningitis: The measurements of salivary ADA activity showed significantly higher activity levels in pigs with meningitis caused by S. suis (median 12,480 U/L, minimum–maximum range 4928–35,360 U/L) compared with healthy pigs (median 1072 U/L, minimum–maximum range 281.6–3008 U/L) (p < 0.001) (Figure 7).